Typical methods for transmitting data use a number of sub-carriers which are modulated by quadrature magnitude modulation, and applied, for example, to QAM of digital cable TV, to DSL of a metal twist-pair, etc. These methods concentrate on the frequency of each carrier. These methods demodulate the signal by applying, for example, a digital filter or FFT and use an impulse response result as coefficients of a filter. For this reason it takes a comparatively long time to detect the amplitude of a carrier because the methods perform detection until there appears to be a same continuous wave form.